The Army could lose 110,000 soldiers — nearly one in four on active duty — as well as new gear and weaponry as the Defense Department makes sweeping cuts to balance its budget.

Army leadership recently settled on an active-to-reserve ratio in which the reserve forces will comprise roughly 52 percent of the active force. If that ratio is employed, the reserves could drop from 555,000 to as low as 410,000 troops.

Personnel costs cover more than half of the Pentagon budget, and are off limits when cuts are made. Cuts to end strength save money but are limited by Congress. That means the bulk comes out of the training and equipping of forces.

Army Chief of Staff Gen. Ray Odierno on July 29 said that if he were asked to deploy 20,000 troops today, he could not guarantee they would be trained to the level they should be, and the result would be more casualties.

That is one reason the Pentagon is pressing for immediate change.

Defense Secretary Chuck Hagel has not made any program or force structure decisions. But he said “it makes sense to take another look at the Army’s force structure” as the service emerges from a decade-plus of war and transitions to protracted, large-scale counterinsurgency operations.

The cuts would come in one of two ways, Hagel said. One option would keep more troops but reduce capability. Smaller cuts would reduce Army end strength to between 420,000 to 450,000 in the active component and between 490,000 to 530,000 in the reserves.

To maintain regional power projection, the service would sacrifice myriad costly programs such as the Ground Combat Vehicle, new helicopters, unmanned technologies, advanced communications and cyber enhancements. Special operations forces would see a considerable cut, as well.

Hagel said such cuts would cause “a decadelong modernization holiday,” in which troops could find equipment and weapons “less effective against more technologically advanced adversaries.”

The second option would cut more soldiers to preserve high-end capabilities. This Army would end up with between 380,000 to 450,000 well-trained and technologically dominant active troops — but it would be able to go fewer places and do fewer things, and responding to multiple contingencies would be nearly impossible.

“We’re not proposing a 380,000 Army. We’re not advocating that,” Hagel said. “This is an honest range of what this review has produced.”

The Army is already cutting the active force by 80,000 soldiers to bring end strength to 490,000 by fiscal 2017. It also plans to cut 13 brigade combat teams and reorganize the remaining 32 by adding a third maneuver battalion to the armored and infantry BCTs and beefing up each brigade’s engineer and fires capabilities.

These cuts are the result of the Budget Control Act of 2011, and Army leaders have repeatedly warned that sequestration could mean deeper cuts in the future.

A picture of the possibilities can be found in a think-tank exercise.In May, the Center for Strategic and Budgetary Assessments teamed with the Center for Strategic and International Studies, American Enterprise Institute and Center for a New American Security to compare how these cuts could unfold over the next decade.

All four expect six active-duty armored brigade combat teams to be cut. Other anticipated cuts and additions include:

■CNAS: The addition of one active infantry BCT while 14 would be cut from the reserves, five reserve armored BCTs cut, one reserve Stryker BCT cut and the elimination of 73,000 active and 84,000 reserve soldiers.

■CSIS: Cutting eight active while adding five reserve infantry BCTs, adding two reserve armored BCTs, cutting five active while adding three reserve Stryker BCTs and a cut of 163,000 active soldiers while boosting the reserves by 100,000 soldiers.

The primary way to prevent these cuts would be to end sequestration. But such legislation would have to go through bipartisan committees and then pass the Senate and House. The legislation must then be signed by President Obama, who has vowed to block attempts to exempt the Pentagon from sequestration.